Initialised by the routine at 34436, and used by the routines at 34574, 35515, 35805 and 36101. Possible values are:

Value	Meaning
0	Willy is neither falling nor jumping
1	Willy is jumping
2-11	Willy is falling, and can land safely
12+	Willy is falling, and has fallen too far to land safely (see 35805)
255	Willy has collided with a nasty or a guardian (see 36101)